In factory automation, production facilities placed in a factory are controlled by a field network over which various types of slave devices which collect and control data of the production facilities and a master device which conducts central control on these slave devices are connected to each other via a communication bus. FIG. 18 is a diagram showing an example of configuration of the field network. In FIG. 18, a field network 100 is built if a master device 200 (programmable logic controller: PLC) and a plurality of slave devices 300 are connected to each other directly or indirectly via a cable 400 or an I/O unit 500 that is included in the devices 300. The slave devices 300 may each include a power supply unit, a motor unit, a counter unit, an image unit, a communication unit, an I/O unit, etc. The communication bus may take on various topologies such as a line, a daisy chain, a tree, and a start, depending on the standard of the field network. To the master device 200, a management device 600 may be connected which is used by a user to set operations of the master device 200, display operation states of the field network 100, and design a network system. The management device 600 is made up of a personal computer etc. in which setting tools are installed.
Patent Document 1 discloses a technology for displaying an access path between a virtual volume of a storage control device having external connection functions and an external volume of an external storage system.
Patten Document 2 discloses a bus communication system that includes a master device and a plurality of slave devices connected to the master device in a daisy chain via a communication bus and can continuously use some of the slave devices rather than stopping all of the slave devices if a switching section is opened accidentally.
Patent Document 3 discloses displaying an image in which an interface unit is attached to a programmable indicator such that if a unit portion is selected in the attachment image, information of the interface unit corresponding to the unit portion may be displayed.
Patent Document 4 discloses a technology of a network device having a plurality of ports, the network device including an indicator lamp that is turned on and off and a display which displays contents about the ports searched for in a database in which set information of the network device is held.
Patent Document 5 discloses a technology for providing hierarchical image display of inter-port connections of an intelligence switch of a network.